Nuclear Issues

While prosecuting its invasion of Ukraine, Russia has relied heavily on nuclear threats, turning the war in Ukraine into a dangerous nuclear crisis with profound implications for the global nuclear order and its two constitutive systems of nuclear deterrence and nuclear restraint. These two interconnected systems, each aiming to manage nuclear possession and reduce the risk of nuclear use, are at once complimentary and contradictory. While tensions between these systems are not new, the war in Ukraine exacerbates them in unprecedented ways. The system of nuclear deterrence seems to be proving its worth by inducing restraint on Russia and NATO, while the system of restraint is undermined by demonstrating what happens to a country not protected by nuclear deterrence. The latter lesson is particularly vivid given Ukraine’s decision to forgo a nuclear option in 1994 in exchange for security assurances from nuclear powers. Russia’s use of nuclear threats as an enabler for escalation and the specter of Russian tactical nuclear use against Ukraine goes well beyond its declared nuclear doctrine. The outcome of the war in Ukraine thus has critical importance for deciding the value of nuclear weapons in global security architecture and for resolving the conundrum between the systems of deterrence and restraint.

As the best documented major crisis in history, in substantial part because Kennedy secretly taped the deliberations in which he and his closest advisers were weighing choices they knew could lead to a catastrophic war, the Cuban missile crisis has become the canonical case study in nuclear statecraft. Over the decades since, key lessons from the crisis have been adapted and applied by the successors of Kennedy and Khrushchev to inform fateful choices.

As diplomats, activists, and researchers converged on Vienna in June for the first meeting of states-parties to the Treaty on the Prohibition of Nuclear Weapons (TPNW), recent tragic world events highlighted how critical it was to convene this multilateral forum on nuclear disarmament.

Since February, Russia’s war against Ukraine has epitomized the grave dangers of a world where nine states possess approximately 12,700 nuclear weapons.¹ That Russia could invade a sovereign state and indiscriminately target its civilian population, while using nuclear threats to deter NATO from intervening, has stunned the world. It offers a stark reminder that possessing nuclear arms can enable abhorrent violations of international law

Although Russia has relied exclusively on conventional weapons for its invasion of Ukraine, behind the scenes lurks Moscow’s massive nuclear arsenal. Hours before Russian forces crossed into Ukraine, Russian President Vladimir Putin reminded the world that his country was “one of the most powerful nuclear states” and that anyone who interfered with his war in Ukraine or threatened Russia directly would face “consequences that you have never faced in your history.” Three days later, as global outrage grew, Putin ordered Russia’s nuclear forces to a higher level of readiness. Even without these explicit threats, Russia’s nuclear deterrent would have prevented Western countries from intervening in Ukraine. Beyond supplying Kyiv with anti-armor and light air defense weapons, they will not come to Ukraine’s defense for fear of nuclear escalation, as U.S. President Joe Biden and other NATO leaders have made abundantly clear. Now that Putin’s attempts to seize Kyiv have been thwarted, there is a risk he will use tactical nuclear weapons to bring Ukraine to its knees. And while this scenario remains unlikely, neither Ukraine nor NATO can do anything to prevent it from happening.

This is a particularly bitter pill to swallow for Ukraine, since it was once home to the world’s third-largest cache of nuclear weapons. After the collapse of the Soviet Union, Ukraine inherited a significant slice of the Kremlin’s nuclear arsenal. But in 1994, the newly independent country decided to surrender that arsenal in exchange for assurances from Russia, the United Kingdom, and the United States that its sovereignty and territorial integrity would be respected. The agreement, known as the Budapest Memorandum, is one that many Ukrainians have come to regret—first in the wake of Russia’s 2014 annexation of Crimea and invasion of eastern Ukraine, and now even more so after its all-out assault on the country. If Ukraine had held on to its arsenal, many have argued, Putin would never have dared to invade the country.

Stephen Walt offers a tentative and far-from-comprehensive survey of what scholars have to say about the war in Ukraine.

Mariana Budjeryn, research associate at Managing the Atom, speaks about the legacy of the 1994 Budapest Memorandum and the remnants of Soviet nuclear weapons in Ukraine.

The hard truth is that the United States now has few good options for containing Iran’s nuclear program. It can persist with the no-deal status quo, allowing Iran to continue inching closer to a bomb while suffering under sanctions. It can pursue a return to the 2015 agreement and then attempt to get Iran to agree to a “longer and stronger” pact, as the Biden team has suggested. It can try for various other deals, either more or less stringent than the 2015 agreement. Or it can attempt to destroy Iran’s nuclear infrastructure with a military strike, possibly setting Tehran’s progress toward a bomb back by a few years but almost certainly provoking retaliation and possibly a sprint toward the nuclear finish line.

The regime built around the 1970 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) has helped curtail the spread of nuclear arms for fifty years. In hindsight, it is remarkable only nine states possess the world’s most powerful weapon. The NPT achieved much success during Cold War bipolarity and U.S. unipolarity in its aftermath. But today, China’s rise and Russia’s resurgence have ushered in a new era of emerging multipolarity. Can the treaty withstand the potential challenges of this dynamic environment? There is a real risk that multipolarity may shake the scaffolding of the nonproliferation regime, presenting a significant test to the NPT’s durability. This article identifies four essential elements of the nonproliferation regime: widespread membership, adaptability, enforcement, and fairness. History suggests bipolarity and unipolarity in the international system largely sustained and promoted these NPT features. When international regimes lack such elements, it sharply curtails their long-term efficacy.

States frequently acquire proof that other states have violated norms. Yet, existing theories do not fully explain how states wield such proof to coerce wrongdoers. Four case studies of nuclear proliferation probe a novel theory of how states coerce norm violators by concealing, sharing privately, or publicizing proof of guilt.

Wedge strategy theory explains how states use strategic arms control to divide adversaries by affecting their trust, threat perceptions, and beliefs about a commitment’s trade-offs. Examining three landmark arms control negotiations shows how the wedge motive was a key component to these negotiations.